Cyclam complexes of Cu(II) and Co(II) as stationary phases for gas chromatography.

New macrocyclic stationary chemically bonded phases were synthesized and tested in gas chromatography conditions. The complexes of 1,4,8,11-tetraazacyclotetradecane with Cu(II) and Co(II) were bonded to the silica support through the (3-chloropropyl)triethoxysilane reactant. The packings obtained were analyzed by diffuse-reflectance ultraviolet-visible spectroscopy (DRUV-Vis), differential thermal gravimetry (DTG), porosimetry, and elementary analysis. Preliminary study of the novel silica gas chromatography (GC) stationary phases containing cyclam complexes was carried out using packed 1/8in. i.d. columns. The study was conducted on: cyclic, linear and branched olefins, aromatic hydrocarbons and ethers. Characterization of interactions between the compounds mentioned and new stationary phases was based upon analysis of Kováts retention indices (I), difference between retention indices for two phases (DeltaI), and molecular retention indices (DeltaM(e)). Results have shown that the new stationary phases interact sufficiently strongly with molecules of high electron density and can be applied in capillary gas chromatography for the analysis of light hydrocarbons.

Retention indices and quantum-chemical descriptors of aromatic compounds on stationary phases with chemically bonded copper complexes.

In this paper, Kováts retention indices determined on stationary phases with chemically bonded copper complexes were correlated with molecular structural parameters for aromatic compounds. Principal component regression (PCR) was applied to extract principal components from the set of 13 descriptors compiled in 5 theoretical models. Extracted components were used to model theoretical retention indices. Significant correlations were found among the retention indices of these compounds and, among others: molecular surface and molecule area, boiling point, HOMO and LUMO energies, dipole moment, dielectric energy, and double bond count. These correlations provide insights into the mechanism of chromatographic retention at the molecular level for the packings and the compounds under study.

Recent advances in gas chromatography for solid and liquid stationary phases containing metal ions.

This review is devoted to the application of metal complexes as column packings and liquid stationary phases in gas chromatography. Particular attention is paid to the stationary phases with nitrogen-containing functional groups (e.g., amine and ketoimine) and beta-diketonates on the modified silica surface. The review also concerns the results of the research on metallomesogenes and chiral stationary phases. The factors influencing the retention mechanism in complexation gas chromatography are discussed. Practical application of the metal chelate-containing chromatographic packings for analytical separation of organic substances is considered.

Chemically Bonded Phases for the Analysis of Trace Amounts of Organic Pollutants.

This work describes some results of identification and determination of bisphenol A (BPA) in powdered milk by applying the gas chromatography. To determine BPA contents in the milk and to reduce the matrix interference associated with the constituents of the powdered milk, we performed the following activities. First, we ultra-centrifuged the dissolved milk solutions. Next, we preconcentrated the analyte in the supernatant using a C(18) and new sorbent with chemically bonded ketoimine group solid phase extraction column. Finally, we used gas chromatography for the determination of BPA in the samples under study. A recovery of bisphenol A from spiked milk samples was also performed, with recovery result located at 91% +/- 3%/94% +/- 2%.

Ketoimino groups as silica surface modifiers.

The presented work is devoted to Porasil C silica, with organic compounds bonded to its surface and capable of electron-donor-acceptor (EDA) interactions. These packings are a good base for studying interactions among stationary phases and the adsorbate molecules showing electron-donor properties. The presented work concentrates on the phases containing ketoimino groups at their surface. Copper and chromium chlorides were bonded through these to the surface. Physicochemical characteristics of the obtained packings were determined by the use of elemental analysis, differential scanning calorimetry (DSC) and inverse gas chromatography. We examined the influence of the surface modification on the retention parameters of the nucleophilic compounds.

Comparative studies of gas chromatographic properties of new packings with chemically bonded complexes.

Specific interactions of aliphatic linear and branched hydrocarbons as well as cyclic and aromatic hydrocarbons with new packings containing chemically bonded complexes of transition metals are studied. The possibility of using these packings to separate these compounds is also discussed. The packings under study contain complexes of Cu(II) and Cr(III) chemically bonded to the silica surface. Chlorides of these metals are bonded to the silica surface by the use of the ketoimine group originally from 2-(3-triethoxysililpropylimino)-3-(n-buthyl)-pentanon-4. In order to determine an influence of the performed modification to gas chromatographic properties of the packings, such retention parameters as retention factor, retention index, molecular retention index, and specific retention volume are measured for these compounds. Based on the obtained values, a trial is taken to determine an influence of the nature of the bonded metal from the complex on the retention of the adsorbates under study and a dependence between a structure of an adsorbate molecule and values of charge-transfer interactions with the bonded metal complexes.

A six week double blind, placebo controlled, crossover study of the effect of misoprostol in the treatment of aspirin sensitive asthma.

BACKGROUND: Prostaglandins of the E series and misoprostol (a stable analogue of prostaglandin E(1)) prevent bronchoconstriction following aspirin ingestion or inhalation in subjects with aspirin sensitive asthma. A study was undertaken to investigate the influence of misoprostol on the course of aspirin induced asthma. METHODS: A double blind, crossover, randomised, placebo controlled study was performed in 17 patients with aspirin sensitive asthma (13 women) aged 26-68 years. All subjects had aspirin sensitivity confirmed by means of oral aspirin or inhaled lysine aspirin challenge. Misoprostol (Cytotec, Searle, 800 or 1600 microg daily according to individual tolerance) or placebo were administered over a period of six weeks. Morning and evening peak expiratory flow rate (PEFR), beta(2) agonist use, asthma and rhinitis severity scores, and defaecation score were measured daily. At the beginning and end of each treatment period spirometric tests were performed and blood was taken for eosinophil count. Eight subjects took misoprostol at a dose of 800 microg and nine subjects at a dose of 1600 microg daily. RESULTS: No differences were seen in asthma control between misoprostol and placebo except for the rhinorrhoea score which was lower on misoprostol during the period of the study. CONCLUSION: Misoprostol in a daily dose of 800 or 1600 microg does not significantly improve asthma control in subjects with aspirin sensitive asthma.

[Comparison of the influence of celiprolol, metoprolol and atenolol on pulmonary ventilation in patients with asthma]. / Porównanie wplywu Celiprololu, Metoprololu i Atenololu na wentylacje pluc u chorych na astme oskrzelowa.

Usage of beta-blocking agents in patients with bronchial asthma is restricted due to their ability to precipitate bronchospasm. Celiprolol beta1-selective beta-blocker with associated beta2-agonist activity gives brand new possibilities of treatment with beta-blockers in asthmatics. The aim of the study was to compare the pulmonary effects of single dose of celiprolol (200 mg), atenololol (25 mg), metoprolol (50 mg) and placebo. Ten stable asthmatic patients, aged 21-60 years (mean age 44.1 yrs.) were studied. During four separate visits with 3 days wash-out period physical examination, ECG recordings were done and lung function tests (FEV1, FVC, FEF25-75), blood pressure, heart rate and saturation were recorded. All parameters were measured again after 45, 90, 150 and 210 minutes from the beginning of the visit. On the contrary to metoprolol and atenolol single dose of celiprolol and placebo did not significantly affect respiratory functions (FVC--area under curve). There was significant decrease of FEV1 calculated as area under curve (AUC) after application of metoprolol in comparison to celiprolol. There were no significant changes in FEV1 after use of atenolol and celiprolol. Celiprolol ian dose 200 mg can be safely used in asthmatic patients.

The influence of misoprostol (synthetic analogue of prostaglandin E1) on aspirin-induced bronchoconstriction in aspirin-sensitive asthma.

It is believed that aspirin (ASA) and other nonsteroidal anti-inflammatory drugs elicit dyspnea in ASA-sensitive asthmatics by blocking cyclooxygenase. It is unclear whether this bronchospasm is due to the shunting of arachidonic acid into the lipoxygenase pathway or to the removal of a cyclooxygenase product which prevents bronchospasm. Diminished tissue concentration of PGE may cause bronchoconstriction. PGE also modulates mast cells, decreasing the release of anaphylaxis mediators. The authors investigated the influence of a synthetic analogue of PGE1-misoprostol (Cytotec, Searle)-on post-aspirin bronchoconstriction in seven ASA-sensitive asthmatics. On the first day, the effect of a placebo was studied. On the second day, the bronchodilatory effect of misoprostol (Cytotec, Searle) alone was examined. After a few days, a predetermined threshold dose of ASA was administered. Seven days later, at least 400 micrograms of misoprostol +200 micrograms 2 h later, together with a predetermined ASA dose, were administered. In all but one patient, the protective influence of misoprostol on ASA-induced bronchoconstriction was observed. The maximum drop in FEV1 (forced expiratory volume in one second) in % after ASA in each of the patients was 40, 25, 24, 33, 47 and 54, and after ASA with misoprostol 10, 9, 4, (+8), 10, (+2) and 45, respectively. Misoprostol given together with ASA attenuated aspirin-induced bronchoconstriction, reaching statistical significance at 3 and 3.5 h. It also diminished extrapulmonary symptoms.

[The influence of misoprostol on post-aspirin bronchoconstriction in patients with aspirin sensitive asthma]. / Wplyw misoprostolu na poaspirynowe zwezenie oskrzeli chorych na astme z nadwrazliwoscia na aspiryne.

It is believed that aspirin (ASA) and other nonsteroidal antiinflammatory drugs elicit dysponea in ASA sensitive asthmatics by blocking the cyclooxygenase. It is unclear whether this bronchospasm is due to shunting of arachidonic acid into the lipooxygenase pathway or removal of cyclooxygenase product which prevent bronchospasm. Diminished tissue concentration of PGE may cause bronchoconstriction. PGE play also modulatory function to mast call decreasing the release of mediators of anaphylaxis. There are some evidences concerning the mast cell degranulation in postaspirin reaction in ASA sensitive asthmatics. The authors investigated the influence of synthetic analogue of PGE1--misoprostol (Cototec, Searle) on the postaspirin bronchoconstriction in seven ASA sensitive asthmatics aged 33-62. Aspirin threshold doses ranged from 10 to 150 mg. Postaspirin bronchoconstriction begun usually within 1-2 hrs after digestion of ASA and 200 micrograms were additionally given 2 h later. Seven days later misoprostol (400 micrograms) was administered together with previously determined dose of ASA. One the other day the bronchodilating effect of misoprostol alone was examined. In all but one patients we observed the protective influence of misoprostol on ASA induced bronchoconstriction. Max. fall in FEV1 in % after ASA in each of the patients was 40, 25, 24, 33, 47 and 54, and after ASA with misoprostol, respectively 10, 9, 4, (+8), 10, (+2) and 45. Misoprostol given together with ASA attenuated aspirin-induced bronchoconstriction reaching statistical significance at 3 and 3.5 h, and also diminished extrapulmonary symptoms. The authors discuss the possible mechanism of protective influence of misoprostol.